Tobacco feed and transport unit in a machine for manufacturing tobacco products

ABSTRACT

Shredded tobacco is fed into and transported through a cigarette maker by a unit that includes at least one transport roller, driven in rotation about a longitudinal axis and equipped with a plurality of radial pins projecting radially from a peripheral surface, by which the flow of tobacco is taken up and directed along a predetermined feed path toward a unit that forms it ultimately into at least one continuous stream; the feed and transport unit is also equipped with at least one sensing device, offered to the peripheral surface of the roller and serving to detect any points where pins may be missing or damaged.

BACKGROUND OF THE INVENTION

The present invention relates to a tobacco feed and transport unit in a machine for manufacturing tobacco products.

The prior art embraces cigarette makers equipped with a feeding and conveying unit that comprises an infeed chamber from which shredded tobacco is taken up by a carding unit and directed into a descending duct or chute. At the bottom end of the chute, the tobacco is taken up by a toothed outfeed assembly and deposited on a conveyor belt that carries it toward the bottom inlet end of an ascending duct or chimney. The top end of the chimney coincides with the outfeed end of the tobacco feed and transport unit, and is enclosed by a conveyor consisting in a looped air-permeable aspirating belt such as will attract the tobacco, rising through the chimney as a continuous flow of distinct particles, and cause it to form progressively into a continuous stream.

The stream of tobacco forming thus externally of the chimney is directed by the aspirating belt loop toward an ecreteur, or trimming station, of which the function is to reduce the stream of tobacco to prescribed and uniform cross sectional proportions. The trimmed tobacco stream is then released by the aspirating belt to the entry point of a station where a continuous cigarette rod is formed.

The carding unit consists typically in a carding drum of which the surface of revolution presents a plurality of pins serving to take up and pick the shredded tobacco.

In addition, the toothed outfeed assembly at the bottom end of the chute comprises a further carding roller and an impeller roller, both presenting a pinned surface of revolution.

Finally, it is also the practice to use further rollers, structurally similar to those mentioned above, as a means of advancing the tobacco through the feed and transport unit.

The interaction between the pins and the compact mass of tobacco can result in a partial breakage of the pins, or even in their complete detachment from the roller. Any fragmented or whole pins separated from the roller will find their way into the mass of tobacco and must then be removed by procedures familiar to a person skilled in the art.

Moreover, the properties of tobacco transported by rollers with missing or damaged pins will be of a lower grade than those of tobacco transported by rollers with all pins intact, and this can affect the quality of the cigarettes ultimately.

To verify possible degradation of the rollers in tobacco feed and transport units of conventional embodiment, the machine must be stripped down and the pins examined visually one by one to locate any that may be broken or missing. It follows that the cigarette maker must necessarily remain idle for an extended period while the inspection is conducted, and that production will be lost as a result.

The object of the present invention is to provide a tobacco feed and transport unit in a machine for manufacturing tobacco products, such as will be unaffected by the aforementioned drawbacks.

One object of the invention, in particular, is to provide a tobacco feed and transport system that will allow damaged or unseated carding pins to be located swiftly and easily.

SUMMARY OF THE INVENTION

The stated object is realized according to the present invention in a tobacco feed and transport unit forming part of a machine for manufacturing tobacco products, comprising at least one transport roller set in rotation about a longitudinal axis, presenting a plurality of pins positioned on a peripheral surface of revolution and oriented radially away from the longitudinal axis, by which tobacco is taken up and caused to advance along a predetermined path toward a unit where it is formed into at least one continuous stream. In the device disclosed, a sensing device associated with the at least one transport roller serves to verify the presence and/or the integrity of the pins.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

FIG. 1 shows a portion of a cigarette maker, viewed schematically in perspective and cut away in part, comprising a tobacco feed and transport unit embodied according to the present invention;

FIG. 2 shows a detail of the unit in FIG. 1, viewed in perspective;

FIG. 3 shows the detail of FIG. 2, enlarged and in a longitudinal section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, which shows an infeed portion of a cigarette maker, the infeed portion is denoted 1 in its entirety and comprises a tobacco feed and transport unit 2 serving to transform a mass of shredded tobacco into a continuous flow of tobacco particles.

The components of the feed and transport unit 2 are housed in a vertically extending enclosure 3 delimited uppermost by a horizontal wall 4 and on either side by two vertical walls 5 and 6.

The infeed portion 1 presents an inlet duct 7 extending upward from the horizontal wall 4, and below the duct, internally of the enclosure 3, a power driven toothed roller 8 by which the shredded tobacco 9 is directed down into a lower chamber 10 delimited at the bottom by a conveyor belt 11.

The chamber 10 accommodates a carding drum, or roller 12, rotatable about an axis 12 a transverse to the two side walls 5 and 6, which forms part of a carding unit 13 and occupies a position adjacent to the downstream end of the belt 11.

In addition to the carding roller 12, the unit 13 comprises a proportioning roller 14 set in rotation substantially tangential to the carding roller 12 and in the same direction.

With this arrangement, the shredded tobacco 9 is directed by the toothed roller 8 onto the belt 11 and then toward the carding roller 12, whereupon a layer of the shredded tobacco 9 substantially equal in thickness to the radial dimension of the carding teeth is transferred by the roller 12 away from the chamber 10 and beyond its position tangential to the proportioning roller 14.

Also associated with the carding unit 13 is an impeller roller 15 rotatable about an axis parallel to the axis 12 a of the carding roller 12, of which the function is to take up the layer of tobacco 3 from this same roller 12 and shower the constituent particles, in the direction denoted F1, down into a substantially vertical descending duct or chute 16 delimited by a pair of transverse walls 17 and 18 extending parallel one with another and with the axis 12 a of the carding roller 12.

The bottom end of the chute 16 is located facing the periphery of a take-up assembly 19 comprising a take-up roller 20, functioning also as a carding or picking roller, and an impeller roller 21 combining with the take-up roller 20 to transfer the shredded tobacco 9 away from the chute 16.

The take-up roller 20 rotates about an axis 20 a parallel to the axis 12 a of the carding roller 12, and is designed to project the tobacco 9 in the form of distinct particles onto a transfer belt 22 moving from right to left as seen in FIG. 1, and angled upward with the runout end located beneath the inlet of an ascending duct or chimney 23.

The top outlet end 24 of the chimney 23 connects with a unit 25 by means of which to form at least one continuous stream 26 of tobacco 9, or in the case of a machine with two tobacco rod processing lines as in the example of FIG. 1, with a unit 25 forming two such continuous streams 26.

The stream 26 of tobacco 9 is advanced toward a garniture assembly, not illustrated, by which it will be formed into a continuous cigarette rod.

All the aforementioned rollers 8, 12, 14, 15, 20 and 21 of the unit 2 serving to feed and transport the tobacco 9 are typified by the same structure. Each one of the rollers 8, 12, 14, 15, 20 and 21, referred to generically hereinafter as a transport roller 27 and illustrated in FIGS. 2 and 3, is rotatable about a relative longitudinal axis 27 a and presents a plurality of pins 28 occupying the peripheral surface 29.

The pins 28 are oriented radially away from the longitudinal axis 27 a of the roller 27, in such a way that the tobacco 9 will be taken up and carried along a predetermined path extending from the inlet duct 7 toward the unit 25 by which the stream 26 of tobacco 9 is formed.

Whilst the rollers 8, 12, 14, 15, 20 and 21 in the example illustrated are structurally similar one to another, the transported tobacco particles will vary in size, and accordingly, the axial and circumferential spacing of the pins 28, hence their density, are selected on the basis of the type and condition of the tobacco 9 handled at each stage along the predetermined path.

To advantage, the feed and transport unit 2 also comprises at least one sensing device 30 serving to verify the presence and/or integrity of the pins 28 associated with at least one transport roller 27 of the unit 2.

Preferably, each of the rollers 8, 12, 14, 15, 20 and 21 illustrated in FIG. 1 is equipped with a respective sensing device 30 serving to verify the integrity of the respective pins 28. To illustrate the structure of the unit 2 more clearly, FIG. 1 indicates one such sensing device 30 associated with the drum or roller 12 of the carding unit 13, and another device 30 associated with the take-up roller 20.

The pins 28 are fashioned in conventional manner from ferromagnetic material and, in a preferred embodiment, the sensing device 30 will comprise at least one inductive sensor 31. Positioned in close proximity to the pins 28, the inductive sensor 31 is able to pick up the magnetic field generated by the selfsame pins 28 and to detect any change in the strength of the field occasioned by the absence or degradation of one or more pins.

With reference to FIGS. 2 and 3, which show the generic transport roller 27, the device 30 includes at least one sensing unit 32 presenting a plurality of sensors 31 arrayed in closed order one alongside another and positioned facing the pins 28 of the roller 27. The sensing unit 32 occupies a fixed position, and is placed so that the pins 28 will pass beneath the sensors 31 when the roller 27 is set in rotation.

In the case of an appreciably long roller 27, the device 30 will incorporate a plurality of sensing units 32 arrayed in closed order one beside another along the longitudinal dimension of the roller 27 and preferably staggered in the circumferential direction, as illustrated in FIG. 2.

Each sensing unit 32 extends partially around the circumference of the respective roller 27.

The pins 28 are arranged typically in a plurality of rows 28 a, each passing around the circumference of the roller 27. The rows 28 a of pins 28 in turn are ordered one beside another along the axis 27 a of the roller 27.

Advantageously, to enable an exact identification of the damaged or missing pin or pins 28, each of the sensors 31 belonging to a given sensing unit 32 is placed over just one respective circumferential row 28 a, so as to maximize its sensitivity to the magnetic field generated by the pins 28 of the row in question.

Moreover, to ensure the magnetic effect induced by a row 28 a of pins 28 is suitably isolated from the sensor 31 monitoring an adjacent row 28 a, the face 33 of the sensing unit 32 directed toward the pins 28 will present a plurality of grooves 34, one for each sensor 31, in which the tips presented by the pins 28 of the respective rows 28 a are freely insertable (FIG. 3) during the rotation of the roller 27.

In an alternative version of the device 30, not illustrated in detail, the sensors 31 of a single unit 32 are ordered in ranks lying parallel to the axis 27 a of the respective roller 27, and columns extending transversely to the axis 27 a. Each column of sensors 28 coincides with a relative groove 34 in which a corresponding circumferential row 28 a of pins 28 is freely insertable during the rotation of the roller.

The sensors 31 are connected to a processing unit (not illustrated) integrated, for example, into the master controller of the cigarette maker. The unit in question monitors the signals received from the sensors and, in the event of a break in continuity being detected, trips an alarm output signal that will also pilot the feed and transport unit 2 to shut down automatically and indicate the position of the missing or damaged pin.

It thus remains only for the operator to replace the missing or damaged pin 28, already identified by the machine, without the need to search through the multitude of pins presented by the roller 27.

The objects stated at the outset are realized in a unit according to the invention, and the problems associated with the prior art duly overcome, since the breakage of a pin can be detected in real time and the damaged or missing pin replaced swiftly, stopping the machine only for the time necessary to effect the replacement.

Self-evidently, it will be preferable to fit the sensing device 30 to all the rollers of the machine or, where there are cost constraints, at least to those rollers with the more slender pins. 

1. A tobacco feed and transport unit in a machine for manufacturing tobacco products, comprising: at least one transport roller set in rotation about a respective longitudinal axis, presenting a plurality of pins positioned on a peripheral surface of revolution and oriented radially away from the longitudinal axis in such a way that tobacco can be taken up and advanced along a predetermined path toward a unit by which it is formed into at least one continuous stream; at least one sensing device associated with the at least one transport roller, serving to verify the presence and/or the integrity of the pins.
 2. A unit as in claim 1, wherein the pins are fashioned from ferromagnetic material and the at least one sensing device comprises at least one inductive sensor able to detect a change in magnetic field, placed in close proximity to the pins.
 3. A unit as in claim 1, wherein the sensing device includes at least one sensing unit that presents a plurality of sensors arrayed in close order one alongside another and facing the pins of the at least one roller.
 4. A unit as in claim 3, wherein the at least one sensing unit occupies a fixed position, with the pins riding under the sensors during the rotation of the at least one roller.
 5. A unit as in claim 3, wherein the at least one sensing unit extends partially around the at least one roller.
 6. A unit as in claim 3, wherein the pins are arranged as a plurality of single rows, extending each around the circumference of the roller and ordered one beside another along the axis of the selfsame roller, and each sensor of the at least one sensing unit is positioned over one of the rows of pins.
 7. A unit as in claim 3, wherein the at least one sensing unit presents a face directed toward the pins and furnished with a plurality of grooves, each circumferential row of pins riding within a respective groove when set in rotation.
 8. A unit as in claim 3, comprising a plurality of sensing units arranged one beside another along the longitudinal dimension of the at least one roller.
 9. A unit as in claim 8, wherein the single units of the plurality of sensing units are staggered along the circumferential dimension of the at least one roller.
 10. A unit as in claim 2, wherein the sensing device includes at least one sensing unit that presents a plurality of sensors arrayed in close order one alongside another and facing the pins of the at least one roller.
 11. A unit as in claim 4, wherein the pins are arranged as a plurality of single rows, extending each around the circumference of the roller and ordered one beside another along the axis of the selfsame roller, and each sensor of the at least one sensing unit is positioned over one of the rows of pins.
 12. A unit as in claim 4, wherein the at least one sensing unit presents a face directed toward the pins and furnished with a plurality of grooves, each circumferential row of pins riding within a respective groove when set in rotation.
 13. A unit as in claim 5, wherein the at least one sensing unit presents a face directed toward the pins and furnished with a plurality of grooves, each circumferential row of pins riding within a respective groove when set in rotation.
 14. A unit as in claim 6, wherein the at least one sensing unit presents a face directed toward the pins and furnished with a plurality of grooves, each circumferential row of pins riding within a respective groove when set in rotation.
 15. A unit as in claim 4, comprising a plurality of sensing units arranged one beside another along the longitudinal dimension of the at least one roller.
 16. A unit as in claim 5, comprising a plurality of sensing units arranged one beside another along the longitudinal dimension of the at least one roller.
 17. A unit as in claim 6, comprising a plurality of sensing units arranged one beside another along the longitudinal dimension of the at least one roller.
 18. A unit as in claim 7, comprising a plurality of sensing units arranged one beside another along the longitudinal dimension of the at least one roller. 